1. Field of the Invention
The present invention relates to a liquid crystal display.
2. Discussion of the Background
A liquid crystal display (LCD) is one of the most widely used flat panel displays (FPDs), and it includes two display panels on which field generating electrodes are formed, and a liquid crystal layer disposed between the two display panels. A voltage is applied to the field generating electrodes to generate an electric field in the liquid crystal layer. The electric field determines the orientation of liquid crystal molecules of the liquid crystal layer and controls the polarization of incident light to display an image.
Among LCDs, a vertical alignment (VA) mode LCD, in which LC molecules are aligned such that the long axes of the LC molecules are perpendicular to the panels in the absence of an electric field, is spotlighted because of its high contrast ratio and wide reference viewing angle.
In a VA mode LCD, a wide reference viewing angle may be realized by forming a plurality of domains including LC molecules with different alignment directions in one pixel.
To form a plurality of domains in one pixel, cutouts, such as minute slits, may be formed in the field generating electrodes. In this case, the plurality of domains may be formed by aligning the liquid crystal molecules perpendicular to a fringe field generated between edges of the cutout and the field generating electrodes facing the edges.
However, in this structure, the aperture ratio may be decreased, and the liquid crystal molecules disposed close to the cutouts may be aligned vertical to the fringe field, but the liquid crystal molecules far from the cutouts may generate random motion such that the response speed is slow and a reversed direction domain is formed, which may generate temporary afterimages.
Alternatively, a plurality of domains may be formed in one pixel using a light alignment method in which the alignment direction of the liquid crystal molecules and the alignment angle are controlled by irradiating light on the alignment layer. In the light alignment method, it may not be necessary to form cutouts in the field generating electrodes because the aperture ratio may be increased and the response of the liquid crystal may be improved by a pretilt angle generated through light alignment.
On the other hand, a VA mode LCD may have lower side visibility than front visibility. Therefore, one pixel may be divided into two subpixels and different voltages may be applied to the subpixels to solve this problem.
However, when applying the light alignment method, texture may be generated at boundaries between the regions where the liquid crystal molecules are aligned in different directions. The texture decreases the transmittance and appears as spots, which may deteriorate the display characteristics.